Processes for breaking petroleum emulsions



Patented Aug. 25, 19 36 Es PATENT OFFICE' PROCESSES FOR BREAKINGPETROLEUM EMULSIONS Melvin De Groote, St. Louis, Mo., assignor toTretolite .Company, Webster Groves, Mo., a corporation of Missouri I NoDrawing.

4 Claims.

This invention relates to the treatment of emulsions of mineral oil andwater, such as petroleum emulsions, for the purpose of separating theoil from the water.

Petroleum emulsions are .of the water-in-oil type, and comprise finedroplets of naturallyoccurring waters or brines, dispersed in a more orless permanent state throughout the oil which constitutes the continuousphase of the emulsion.

They are obtained from producing wells and from the bottom of oilstorage tanks, and are commonly referred to as cut oil, "roily oil,"emulsified oil and bottom settlings.

The object of my invention is to provide a novel and inexpensive processfor separating emulsions of the character referred to into theircomponent parts of oil and water or brine. V

Briefly described, my process consists in subjecting a petroleumemulsion of the water-in-oil type to the action of a treating agent ordemulsifying agent of the kind hereinafter described, thereby causingthe emulsion to break down and separate into its component parts of oiland water or brine, when the emulsion is permitted to remain in aquiescent state after treatment, or is subjected to other equivalentseparatory procedures.

The treating agent or demulsifying agentused in my present processconsists of a chemical compound characterized by the presence of both aketo fatty acid residue derived from castor oil and a dicarboxy acidresiduein the same molecule; said dicarboxy acid residue being obtainedfrom an acid of the formula type (CHa)c(COOI-I)z, in which n has a valueof at least 5 and not more than 8. y

In a co-pending application for patent of Melvin De Groote, BernhardKeiser and Arthur F. Wirtel, Serial No. 760,033,1lled December 31, 1934,

40 there is described a process for breaking petroleum emulsions bymeans of unpolymerized keto fatty acid bodies or materials. It is wellknown that fatty acids or fatty bodies can be subjected to chemicaltreatment so as to yield keto fatty acids, that is, fatty acids ln whicha ketonic group (a carbonyl group) is present. One example is theconversion of ricinoleic acid into ketohydroxystearic acid. (SeeLewkowitsch "Chemical Technology of Oils, Fats and Waxes, 6th edition,volume 1, page 242) In jfai general 'way, the manufacture of suchket'onic acids is dependent upon the'treatment of an un- Qsaturatedfatty body or fatty acid, such as fricinoleic acid, oleic acid, or thelike, with a "55 halogen, such as bromine, so as to form a halogenApplication December 21, 1935, Serial No. 55,619

addition product, for'example, ricinoleic acid dibromide, which is thenconverted into ricinstearolic acid. Ricinstearolic acid, on treatmentwith sulfuric acid, yields ketohydroxystearic acid.

In a second co-pending application for patent of Melvin De Groote,Bernhard Keiser and Arthur F. Wirtel, Serial No. 760,032, filed December31, 1934, there is disclosed the use of polyketo fatty acid bodies forthe purpose of breaking petroleum emulsions. Polyketo fatty acids may bederived 10 by polymerization of keto fatty acids which have beenpreviously derived in the manner described by Lewkowitsch, mentionedabove.

In the present application, the expression keto fatty acids" or ketofatty acid bodies" is intended to include .both unpolymerized keto fattyacid bodies and polymerized (polyketo) fatty acid bodies. It is moreeconomical in many instances, to prepare the reagent employed in thepresent process from a polyketo fatty acid body than from anunpolymerized one, the reason being that 7 it is more economical toproduce polyketo fatty acid bodies than unpolymerized keto fatty acidbodies.

In the production of polyketo fatty acids or their salts or esters, bypressure oxidation at relatively low temperatures, one may employ anysuitable unsaturated, hydroxylated fatty material, such as castor oil,ricinoleic acid, diricinoleic acid, and other materials of the kinddescribed in the aforementioned applications for patent of De Groote,Keiser and Wirtel, or any other suitable material. A third co-pendingapplication of Melvin De Groote, Bernhard Keiser and Arthur F. Wirtel,Serial No. 760,031, filed December 31, 1934, discloses a novel methodfor producing polyketo fatty acids and their salts and esters, saidmethod contemplating pressure oxidation at relatively low temperatures,such as 135 C. or less, and

the product of said method consisting of materials 40 high in polyketofatty acids, which have the same characteristics as polyketo fatty acids'derived by esterifying or condensing a keto fatty acid, such asketohydroxystearic fatty acid with ricinoleic acid, or diricinoleicacid, or oleic acid, or triricinclein.

Briefly described, the method just referred to for producing suchpolyketo fatty acids by pressure oxidation, consists in mixing anunsaturated, hydroxylated, fatty body of the kind previously described,such as castor oil, with not over 10% of a true drying oil, such aslinseed oil, or perilla oil, or the acids thereof, and subjecting thesame to pressure oxidation at approximately 15 to '75 lbs. gaugepressure by means of ordinary moist air and at a temperature of not over135 C., and preferably at about 120 0., for approximately -10 to 30hours. A small amount of a fat splitting sulfonic acid, such asapproximately 5 of Petrofi. reagent (oil-soluble petroleum sulfonicacids) may be present during acid," which may be indicated by thefollowing formula However, oxidation not only takes place at thelhydroxyl position, but also at the ethylene linkage, with probably theabsorption of oxygen and then conversion into hydroxyl groups, and thusthe ketonic acid produced may represent a saturated, dihydroxy. acidwhich may be indicated by the following formula:

on on OHs-(CHflr-CCF-CHa-AH-H--(CH:)7COOH However, it is well known thatoxidation reactions tend to polymerize or form ester acids,

7. others, etc., and thus the resultant product represents ketonic acidsin the polymerized form, f. e., derived from two or more molecules, atleast one (u of which must contain a ketonic group. Obviously, suchketonic fatty acids may be of theoxy or hydroxy type as well.

The formation of ketohydroxystearic acid in the-usual manner (seeLewkowitsch Chemical Technology of Oils, Fats and Waxes, 6th edition,volume 1, page 242) with subsequent reaction with ricinoleic acid,diricinoleic acid, oleic acid,

triricinolein, etc. results in a compound representing substantiallynothing other than polyketo acids. On the other hand, I am aware thatthe products obtained by pressure oxidation in the manner referred topreviously,- may result in products containing asigniflcant amount ormajority of polyketo acids, but may contain certain other-non-ketohicmaterial of the kind presentin various conventional .or special blownoils. Since such non ketonic materials are also effecti've quitefrequently for the treatment of oil held emulsions, and therefore,inproducing the demulsifying agent employed in. my present process, Iprefer to use the. impure form of polyketo acids or their salts'orresters, as obtained by pressure oxidation. This ispurely a matter' of"economy. The pure forms, relatively free from extraneous materials, maybe employed. V

I am fully aware that migration may take place in a fatty molecule. Forinstance,'that the formation' of stearolactone from hydroxystearic acidappears to depend on the migration of the alcoholiform hydroxyL. I amalso aware that inthe case of the common non-fatty ketonic acid,aceto-acetic acid, that certain reactions are how to .take place whichsuggest that acetoacetic acid may, as far as those reactions areconcerned, react more as an aldehyde or as an aldehydic' acid thanas aketonic acid. Such wandering of a hydrogen atom and change in positionof a double bond is referred to as ketoerlolic tautomerism (Bernthsen,"Textbook of Organic Chemistry, 2nd edition, 1931, page 231). I believethat this or a comparable change may 5 take place in these polyketonicacids or bodies previously described, and possibly, in regard to somereactions, these polyketo acids or esters thereof act more as if theywere aldehydic acids, or esters, or salts thereof. In other words, ifthese polyketonic acid bodies are to be used in a mixture wherealdehydic acids would be incompatible, it is also likely that thesepolyketonic acids or their esters may be incompatible, for the reasonthat they really may be aldehydic acid bodies. It is to be noted thatthe reagents of the kind employed for determining the presence of thecarbonyl group in ketones also usually detect the presence of thecarbonyl group in aldehydes. It is to be understood that in the appendedclaims where the products are characterized by the presence of ketonicradicals, that such acids might ultimately prove to be aldehydic acids,or at least, convertible under certain conditions of use, or else undercertain conditions of identification, possibly they become convertedinto aldehydic acids, and it is not intended that the word ketonic" orketo" be interpreted as excluding the meaning of aldehydic" in the sensepreviously described or discussed, 1. e., that both have the carbonyl(CO) radical present, and their ultimate composition in carbon atoms,hydrogen atoms, and oxygen atoms, is identical.

In United States Letters Patent No. 2,023,995, to Melvin De Groote andBernhard Keiser, dated December 10, 1935, there is disclosed a processfor breaking emulsions by means of esters derived by reaction between adibasic acid of the type (CH2)n(COOH)2, in which n has a value of atleast 5 and not more than '8, and a hydroxylated fatty body, such asricinoleic acid, triricinolein, etc. More specifically, the dibasiccarboxy acids employed to produce the demulsifying agent used in theprocess of said De Groote and Keiser patent includes the following;

Pimelic acid (HOOC(CH2)5COOH) Suberic acid (Hoocwrnncoom Azelaic acid(HOOC(CH2)1CO0H) Sebacic acid (noomcnmcoom due in the same molecule, thedicarboxy acid residue being derived from an acid of the; type(CH2)n(COOH)2, in which n has a value of at 0 least 5 and-not more than8. The formation of such materials is relatively simple, since .the ketofatty acid may represent the acid alcohol type of reagent. In the samesense that ricin'oleic acid is an acid alcohol, one may obtain the samereaction from one molecule of keto fatty acid and one molecule of thedibasic carboxy acid as one would obtain from a molecule of ricinoleicacid and a molecule of oxalic acid. Thus, one may form a new acid havingtwo carboxyl radicals by 70 esterification between one of the carboxylichydrogens of the dibasic carboxy acid and the 'hydroxyl of the acid.Needless to say; just as one can form a trimolecular acid, such astriricinoleic acid, likewise, one can combine two molecules of 76 ketofatty acid with one molecule of a dibaslc carboxy acid by reactioninvolving the two carboxyl radicals of the dibasic acid. Likewise, anyother alcohol acid type of material such as ricinoleii: acid,hydroxystearic acid, or the condensation product of ethylene glycol withoxalic acid or 'phthalic acid or maleic acid, may serve as a which thereis no free carboxyl, such as a salt.

bridge or a connecting link by combination with a molecule of keto fattyacid and a molecule of 'a dibasic carboxy acid. Such material used as aconnecting link or bridge, of course, must be amphoteric, if it can beemployed to combine with a hydroxyl radical of an oxy acid and thecarboxyl' radical of a dibasic carboxy acid. Obviously, where itcombines with the carboxyl of an acid, one may use an oxy acid materialin or ester. v

Likewise, in any case where a carboxylic .hydrogen remains, suchcarboxylic hydrogen may be converted into salt by neutralization with asuitable base, such as sodium hydroxide, potassium hydroxide, calciumhydroxide, triethanolamine,

etc. Such free carboxylic hydrogen may be converted into an ester, suchas methyl ester, ethyl ester, propyl ester, or into an aromatic, cyclic,or aralkyl ester.

The keto fatty acid may be of the hydroxy type. Such keto acids may, ofcourse, act as an alcohol, and thus combine directly with the carboxylof a dibasic carboxy acid.

Other means of combination are readily available, such'as the formationof a diglyceride in which a molecule of keto fatty acid and a moleculeof a dibasic carboxy acid is united with a molecule of glycerol, so asto leave one hydroxyl group and one carboxyl group uncombined.

Likewise, such reaction could be continued seas to yield a triglyceridefree from any uncombined hydroxyl or carboxyl groups. Likewise, twomolecules of a keto fatty acid could be reacted with one molecule ofglycerol, and subsequently further reacted with one molecule of adibasic carboxy acid, so as to yield a product in which there isaresidual carboxyl group. One molecule of a keto fatty acid and onemolecule of adibasic' carboxy acid'can be united by means of ethyleneglycol or some similar glycol.

As previously remarked. where a keto fatty acid is acting by virtue ofits alcoholic hydroxyl, i. e., acting as an alcohol, one need not employthe acid itself, but one may employ any suitable salt, such as a sodiumsalt, ammonium salt, potassium salt or an amine salt, such as atriethanolamine salt, etc. Where the oxy acid is acting .by virtue ofits carboxylic hydrogen, one need not employ the acid itself, but onemight employ a-combination wherein the alcoholic hydroxyl has alreadycombined with some other acid, such as ricinoleic acid. All thesereactions are essentially'esteriflcation reactions. Esteriflcationreactions are best promoted at a fairly high temperature, and preferablyslightly above the boiling point of water. The passing of dryhydrochlric;;acid gas hastens the reaction. Any conventional means maybe employed to hasten these reactions, such as the passing of drycarbonic added thereto 314 lbs. of glycerol. The mixture is heated toapproximately 110 C. and dry carbon dioxide gas is passed through themixture with constant stirring, until the acid value remains constant,based on tests of samples taken at hourly intervals. If the reactiondoes not proceed rapidly enough, a higher temperature, say, 125 to 1350., may be employed. If desired, dry hydrochloric gas, or even driedair, may be substituted for the dry carbonic acid gas. The product thusobtained is a very efficient demulsifying agent, especially afterdilution with some suitable solvent, so as to reduce its viscosity. Oneor more of the following will serve as a suitable solvent: benzol,solvent naphtha, kerosene, or propyl alcohol.

If desired, any free acidity which is present in .7

the preferred reagent may be neutralized by triethanolamine or by anyother suitable amine, such as monoamylamine, benzylamine, etc. The freeacidic carboxyl may be converted into a salt, such as sodium, potassium,or ammonium salt. The free acidic carboxyl, of course, may be combinedwith an alcohol, such as ethyl, methyl, or propyl alcohol, or withglycerol.

Conventional demulsifying agents employed in the treatment of oil fieldemulsions are used as such, or after dilution with any suitable solvent,

such as water; petroleum hydrocarbons, such as gasoline, kerosene, stoveoil; a coal tar product, such as benzene, toluene, xylene, tar acid oil,cresol, anthracene oil, etc. Alcohols, particularly aliphatic alcohols,such as methyl alcohol, ethyl alcohol, denatured alcohol, propylalcohol, butyl alcohol, hexyl alcohol, octyl alcohol, etc., may beemployed as diluents. Miscellaneous solvents, such as pine oil, carbontetrachloride, sulfur dioxide extract obtained in the refining ofpetroleum, etc., may be employed as diluents. Similarly, the material ormaterials employed as the demulsifying agent of my process may beadmixed with one or more of the solvents customarily used in connectionwith conventional demulsifying agents. Moreover, said material ormaterials may be used alone or in admixture with other suitable wellknown classes of demulsiiying agents, such as demulsifying agents of themodified fatty acid type, the petroleum sulfonate type, thealhlatedsulfa-aromatic type, etc.

It is well known that conventional demulsifying agents may be used in awater-soluble form, or in an oil-soluble form, or in a form exhibitingboth oil and water solubility. Sometimes they may be used in a formwhich exhibits relatively limited water solubility and relativelylimited oil solubility. However, since such reagents are sometimes usedin a ratio of 1 to 10,000, or 1 to 20, 000, or 1 to 30,000, such anapparent insolubility in oil and water is not significant, because saidreagents undoubtedly have solubility within the concentration employed.This'same fact is true in regard to the material or materials employedas the demulsifying agent of my process.

In practising my process a treating agent or de- 'various ways or by anyof the various apparatus now generally used to resolve or breakpetroleum emulsions with a chemical reagent.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A process for breaking petroleum emulsions of the water-in-oil type,which consists in sub- :Iecting the emulsion to the action of ademulsifying agent comprising a, chemical compound, characterized by thepresence of both a keto fatty acid residue derived from castor oil and adicarboxy acid residue in the same molecule; said dicarboxy acid residuebeing obtained from an acid of the formula type (CH2)n(COOH) z, in whichn has a value of at least 5 and not more than 84 I 2. A process forbreaking petroleum emulsions of the water-in-oii type, which consists insubjecting the emulsion to the action of a demulsitying agent comprisinga chemical compound in the form of a salt, characterized by the presenceof both a keto fatty acid residue derived from castor oil and adicarboxy acid residue in the same molecule; said dicarboxy acid residuebeing obtained from an acid of the formula type (CH2)n(COOH)2, in whichn has a value of at least 5 and not more than 8.

3. A process for breaking petroleum emulsions of the water-in-oil type,whichconsists in subjecting the emulsion to the action of a demulsifyingagent comprising a chemical compound in the form of an acid,characterized by the presence of both a kcto fatty acid residue in .r

the same molecule; said dicarboxy acid residue being obtained from anacid of the formula type (CH2)n(COOH)2, in which n has a value of atleast 5 and not more than 8; 4. A process for breaking petroleum emulsioof the water-in-oil type, which consists in subjecting the emulsion tothe action of a demulsii'ying agent comprising a chemical compound inthe form of an ester, characterized by the presence of both a keto fattyacid residue derived from castor oil, and a ,dicarboxy acid residue inthe same molecule; said dicarboxy acid residue'being obtained from anacid of the formula type (CH2)n(COOH)2, in which n has a value of atleast 5 and not more than 8. MELVIN DE GROOTE.

